Video processing system for movement simulation

ABSTRACT

A video processing system for use in creating apparent three dimensional movement of a two dimensional video image on a display screen  20.  At least one set of axes is displayed on the image to be moved. A computer  24,  in response to signals from a user operated stylus  21  and touch tablet  22,  controls the manipulation of image data in an image store  26  to control apparent rotation of the image about, and/or linear movement along, an axis selected by the user. In the described embodiment several sets of linked axes are defined. Rotation or linear movement with respect to an axis is controlled respectively by selecting a marker identifying the axes or a line representing the axis. Selection is made by way of a cursor under the control of the stylus and touch tablet. The system can also display a line representing the user defined movement of e.g. the center of the image.

This is a continuation of application Ser. No. 08/465,969 filed Jun. 6,1995, U.S. Pat. No. 5,714,977, which is a continuation of applicationSer. No. 08/046,479 filed Apr. 12, 1993 (abandoned), which is acontinuation of application Ser. No. 07/410,126 filed Sep. 20, 1989(abandoned), which is a continuation-in-part of application Ser. No.07/159,780 filed Feb. 24, 1988 (U.S. Pat. No. 4,951,040).

FIELD OF THE INVENTION

The present invention relates to a video processing system having afacility for simulating three dimensional movement of a live videopicture.

BACKGROUND OF THE INVENTION

video processing machines for simulating three dimensional movement of alive video picture are known. Hitherto, the controls for such machineshave included switching devices for selecting operations and movementdetectors, such as levers and tracker balls, for defining the temporalnature of the selected effect. These controls provide a means by which auser of the machine can among other things achieve the effect ofapparent three dimensional movement of for example live video pictureson a display screen. However, such controls are limited in that multipleactuations of different levers and switches together with movement ofthe tracker ball are required in order to achieve the desired effect.Thus, efficient use of the machine requires a high level of experienceand dexterity on the part of the user and, whilst highly satisfactoryeffects are achievable using these controls, an undue amount of time canbe spent by the user in achieving desired results.

OBJECTS AND SUMMARY OF THE INVENTION

The principal object of the present invention is to provide a solutionto the above and associated limitations and to provide an improved videoprocessing system for image manipulation to simulate movement.

The invention generally resides in the concept of providing an improvedvideo processing system in which a set of axes can be displayed over animage and the image can be manipulated by reference to said axes by auser by way of input means to realise the desired simulated movementeffect.

According to the invention in one of its aspects therefore there isprovided a video processing system for use in creating apparent threedimensional movement of a video image on a display screen, in whichsystem at least one set of axes is displayed and processing meansresponsive to user operable input means are provided for processingimage data to control apparent rotational movement of the image about,and/or apparent translational movement in the direction of, a userselected axis of said set.

In an embodiment of the invention, to be described in greater detailhereinafter, a plurality of sets of axes are available to be selectivelydisplayed and individual axes within selected sets can be selected bythe user by way of a cursor displayed on the display screen, theposition of the cursor being controlled by use of the user operableinput means, namely in the embodiment in question a pressure sensitivestylus and an associated touch tablet. The spatial relationship betweenthe various sets of axes can be defined by the user by way of the cursordisplayed on the display screen and manipulated by the user with hisstylus and touch tablet. By providing a plurality of sets of axes andproviding for selective movement in each axes set, the system provides ameans by which different levels of movement of an image may be achievedas will become apparent from the following.

A first level set of axes will normally be provided at the centre of apicture, that is to say at the centre of a framed image, and the systemarrangement enables the user to rotate the picture with any axis of suchfirst set or axes or to move the picture with the origin of the axes setalong the line of any axis as required. The first set of axes isnormally set such that two of the axes are arranged to lie parallel tothe x and y directions of the picture (and of the display screen,assuming the picture edges are parallel to the edges of the screen whichwill normally be the case) and a third axis is arranged to beperpendicular to the picture (and to the screen). Translation of thepicture along the x and y axes, when the x and y axes of the picture areparallel to the x and y axes of the display screen, will simply causethe picture to shift left or right and up or down on the display screen,while translation along the z-axis will cause the size of the picture tochange as it moves in 3D space away from or towards the display screen.The effect of rotation of the picture about an axis needs noexplanation.

Higher level sets of axes are also made available to be utilisedsuccessively, and can be located by the user at any desired position inthree dimensional space remote from the first axis location. The originof the first set of axes, also called the picture level axes, (i.e. thecentre of the image) is maintained at a fixed distance in threedimensional space from the origin of the second level axes and in thisway rotation and translation of the picture in relation to a secondlevel axis will cause movement of the picture in three dimensional spaceas though the centre of the picture were fixedly connected to one end ofa rigid arm having its other end located at the origin of the secondlevel axes and movable therewith in rotation and translation. Thus,translation and rotation of the second level axes may be effected tochange the shape and size of the picture to accommodate changes inperspective and viewing position as the image is moved. Further higherlevels of axes may be defined at other points in three dimensional spaceas required. Each level of axes will be maintained at a fixed distancefrom the next higher level axes and in this way complex movements of thepicture through three dimensional space may be defined by the user.

As will be explained in the following, in use of the system of theinvention to simulate three dimensional movement of a video picture, thefirst or picture level set of axes is automatically displayed at thecentre of the picture when the system is activated. The user can thentranslate and rotate the picture level set of axes as required by use ofhis stylus and touch tablet. When a second level set of axes is requiredthis is derived from the picture level set of axes which is, in effect,dragged out to the required origin position of the second set of axes,again by use of the stylus and touch tablet. The second set of axes asthus established are thus oriented identically to the orientation of thepicture level set of axes at the time when the second set of axes areset up. Once the second set of axes has been set up, the user has thefacility to rotate and translate in the second axes with correspondingmovement of the picture. Subsequent axes sets are similarly established,each subsequent axes set being dragged out from the preceding set asabove described in the case of the second and picture level set of axes.All axes sets that are set up by a user remain displayed and the userhas the option to work in any selected one of a series of sets of axesthus established.

In order to facilitate use of the system each set of axes can bedisplayed as a set of lines representing the orientation of each axis inthe set and accompanying labels which identify each axis, the systembeing arranged such that selection of a label by cursor control enablesrotation about the associated axis to be effected and selection of aline enables translational movement along the associated axis to beeffected.

Furthermore, the system may be configured so as to enable the display ofa locus representing the movement of the picture in three dimensionalspace and/or representing the movement of the origin of a user selectedset of axes in three dimensional space. The video picture may comprise asequence of video frames and the system can be arranged such that atleast some of the frames can be defined by the user as key frames whichare displayed at user defined position within the three dimensionalmovement. The locations of other frames in the sequence not having auser defined location can be calculated automatically by extrapolationbetween user defined keyframes. In this case the locations of keyframesin the movement are represented by first markers in the locus displayedon the display screen, and the locations of other frames are representedby second markers in the locus.

Thus according to another aspect of the invention there is provided avideo processing system comprising frames storage means, data processingmeans, a viewing screen and user operable means arranged for cooperationwith said processing means to effect manipulation of frame store data tosimulate movement of a video image in three dimensional space, andwherein the system further comprises means for storing data defining thenature of said manipulations, means for determining address datarepresentative of the positions of a predetermined element of amanipulated video image, and means for displaying connections betweensaid positions to show the movements of said element.

Further features of the invention are as set forth in the appendedclaims and, together with those features above mentioned, will becomeclear from consideration of the detailed description of an exemplaryembodiment of the invention which will be given in the following withreference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a video processing system embodying the present invention;

FIG. 2 shows an example of a typical display generated while using thesystem of FIG. 1; and

FIG. 3 sows a locus representing movement of a point in the picture orthe origin of a set of axes.

DESCRIPTION OF THE PREFERRED EMBODIMENT

A video processing system embodying the present invention is shown inFIG. 1 as comprising a television type monitor 20, a pressure sensitivestylus 21 and touch tablet 22 each connected to a processing system 23.The processing system 23 includes a control computer 24, an addresstransforming circuit 25, an image framestore 26, a graphics framestore27 and a video combiner 28. In operation an input signal is supplied byan input device 29 which for live video from a camera or an output froman analog video tape recorder will include an analog to digitalconverter. Alternatively the input may be in, say, D1 digital format, anapproved digital standard for making digital video tape recordings fromtape, disc or other digital processing system.

The processing system 23 is arranged under software control to enablevideo signal supplied thereto via the input device 29 to be manipulatedframe by frame in real time to produce special rotational andtranslational effects by writing pixels to the image framestore 26 in afirst order and reading them from the framestore 26 in a differentorder. Image manipulation systems which operate in this way are knownand generally work as either read side systems, in which image data iswritten into a store in normal raster order and then read from the storefor display in a different order, or write side systems, in which theorder of the data is changed as it is written to the store and then isread conventionally. One example of a machine which writes to the storein normal raster order and then reads in a different order (read side)is manufactured by the present Assignee and sold under the trade mark“ENCORE” and is described in European Patent Publication No.EP-A-0283159 and in corresponding U.S. patent application Ser. No.159780 and Japanese Patent Application No. Sho 63-62099 the disclosureswhereof are incorporated herein by way of reference. Another machinewhich performs its manipulations while writing to a framestore and thenreads in a conventional way (write side) is manufactured by the presentAssignee and sold under the trade mark “MIRAGE” and is described in UKPatent Applications Nos. 2119594 and 2158671 the disclosures whereof areincorporated herein by way of reference. Write side processing isgenerally the more difficult, and the described embodiment of thepresent invention as represented in FIG. 1 is configured as a read sidesystem though the invention could also be embodied in a write sidesystem.

The system according to the present invention does not require thecontrol panel having switch buttons and a tracker ball that are providedin said earlier ENCORE machine but instead is arranged under softwarecontrol so that all operations can be effected by use of the pressuresensitive stylus 21 upon the touch tablet 22. More particularly, in thesystem of the present invention, a movement of the stylus 21 on thetouch tablet causes the touch tablet to output address signalsrepresenting movements in x and y directions as shown by the axes 30 inFIG. 1. An additional parameter of the movement is defined by thepressure that is applied to the stylus as sensed by means of a pressuretransducer incorporated into the stylus, for example by application ofstylus pressure in an on/off fashion to define start and end points ofan operation, e.g. the origin positions of successively established setsof axes. The stylus 21 and touch tablet 22 enable the user to controlthe movement of a cursor on the display screen and in this way a user isable to select an operation, effect it and store the result withoutlooking away from the monitor 20. The vast number of picture movementsachievable with a system of this type can be combined with previouslyknown image processing features or options such as sizing, cornerpinning etc. selected from a menu displayed on the monitor.

Movement of the stylus swiftly across the edge of the touch tablet (aprocess known as swiping) is arranged in per se known manner to call upa menu of user selectable options which can be displayed anywhere in thescreen, for example in the lower, or upper, quarter of the screen. Themenu may obscure the display area below it or alternatively it may bemade transparent. As the stylus is placed onto the touch tablet a cursoris displayed on the monitor and is controlled (moved) by moving thestylus on the touch tablet. An operation is selected by the user bymoving the stylus so that the cursor appears over the appropriate menuitem and then pressing the stylus onto the touch tablet so as to causethe pressure transducer to output a signal to indicate to the system theselection of the corresponding menu option. The system according to thepresent invention is therefore arranged by its software to be controlledin a very similar way to the video graphics system manufactured by thepresent Assignee and sold under the trade mark “PAINTBOX”.

As can be seen from the exemplary showing of FIG. 2 the image 33 readfrom store 26 has been reduced in size so that it occupies only part ofthe full screen of monitor 20. The system is arranged such thattranslational image movements can be controlled by operation of thestylus on the touch tablet so as to position the cursor over an x, y orz letter associated with a particular set of axes. With the cursor sopositioned, pressing the stylus on the touch tablet (and therebyactivating the pressure transducer therein) cause the respective axis tobe selected and thus allows movement in the selected axis direction tobe effected by further movement of the stylus. Similarly identifying anaxis by placing the cursor over the line representing it and pressingthe stylus to indicate selection allows rotation about that axis to becontrolled by the user. Since the origin of the first set of axes 31 isalways at the centre 32 of the picture, movement in relation to anypoint in 3D space other than in relation to the centre 32 of the picturerequires the operator to ascend to a higher level, i.e. a different setof axes 34, 36, 37.

The on screen menu (not shown) provides for the selection of higherlevel axes. On selecting the second level, say, a second level referencepoint (origin) 34, with its accompanying set of axes orientedidentically to the picture level axes 31, may be positioned anywhere onthe screen by use of the stylus. By further use of the stylus in amanner as above described for the picture level axes 31 movements inthis second set of axes can be effected. At this second level the userinstructions define movements of the origin of the picture level axes 32about the origin of the second level axes 34. Similarly, at the thirdlevel movements of the origin of the second level axes 34 are definedwith respect to the origin of the third level axes 36, and at the fourthand in this case highest level movement of the origin of the third levelaxes 36 is defined with respect to the origin of the fourth level axes37.

FIG. 2 shows the way in which picture movements may be controlled atdifferent hierarchical levels by the use of a series of linked axes. Onthe display screen 20 a first set of axes 31 referred to hereinafteralso as picture level axes, are automatically set up at the centre 32 ofa picture 33 in response to user initiation of the system to enable theuser selectively to rotate the picture with, or translate the picture inthe direction of, any of the axes 31 x, 31 y, 31 z, such rotation and/ortranslation being effected conventionally as hereinbefore described. Twoof the axes 31 x, 31 y lie parallel to the x and y directions of thepicture 33 and initially (before any picture rotation) of the displayscreen 20, and the third axis 31 z is arranged to be perpendicular tothe picture and thus initially (before any picture rotation) to thedisplay screen 20. Each axis 31 a, 31 y, 31 z is represented on thedisplay screen by a line indicating the orientation of the axis and aletter x, y or z identifying the axis, and image manipulation iseffected by operation of the stylus/touch tablet to move a cursor on thedisplay screen and by means of the cursor to select either rotation ortranslation relative to a selected axis. Higher levels of axes may alsobe utilised. A menu (not shown) that is provided on the display screenenables the user to select a higher level axes set, for example secondlevel axes 34, and once selected the axes 34 can be located by use ofthe stylus and its pressure sensitive facility on the touch tablet atany point in three dimensional space and thereafter rotation and/ortranslation in the second axes level can be effected. The distance inthree dimensional space between the origin 32 of the picture level axes31 and the origin of the second level axes 34 is held fixed once it hasbeen set by the user, and is represented by the broken line 35 in thedrawing. Further higher levels of axes, for example third level axes 36and fourth level axes 37, may also be defined at other points in threedimensional space if so required, the origins of such axes being heldrespectively at user defined fixed distances, represented in FIG. 2 bybroken lines 38, 39, from the origins of the axes at the level below.Image manipulation by rotation and/or translation relative to any axisof the successive hierarchical levels of user defined axes is effectedexactly as above described for the picture level axes.

The picture manipulation movements achievable by the present inventionmay be likened to the behaviour of a multiply articulated arm movingthrough three dimensional space. This notional articulated arm wouldhave three links corresponding to the broken lines 35, 38 and 39connected by ball joints at the origins of the axes 34 and 36 and withthe centre 32 of the picture rotatably connected to the link 35 by aball joint at the origin of axes 31 and the link 39 also connected to aball joint at the origin of the axes 37. Since the articulated arm ismerely notional, the links are such as to allow total movement of thepicture 36 apparently in three dimensional space, including thesituation of two links of the arm occupying the same space. The linksystem is set up by the system user who determines the initial positionsof the ball joints 34, 36, 37 and the lengths of the links 35, 38, 39and the user is then free to define movements of the picture byrotations and translations within the link system.

In order to facilitate operation of the system, each level of operation(i.e. each set of axes and associated graphics) advantageously has anassociated color relating to that level so that movements in any givenlevel are represented in its particular color. Thus the axes 31 formovement at the picture level are displayed in a picture level color,and the higher level axes 34, 36, 37 are displayed in different colors.

During the creation of a move, i.e. 3D movement of the picture, only asingle picture frame 33 is read from the image store 26 and displayed onthe monitor 20 and this picture frame 33 remains on the monitor'sdisplay whilst a move is being created. Video data for the or each setof axes 31, 34, 36, 37, and any other information to be displayed overthe picture, for example the cursor, is stored in the graphicsframestore 27 which is addressed in synchronism with the image store 26.However once the move has been defined, sequential frames of live videoetc. may be written to the store 26 via input device 29. The computer 24includes a memory device for storing a sequence of manipulated readaddress signals representing the move. As the move progresses a narrowband of colour can usefully be arranged to move across the top of thescreen to inform the operator how much memory space is available, and inthis way all the information required by the operator is displayed onthe monitor 20. The apparent three dimensional movement of the pictureas defined by the operator is stored as a sequence of address signalsdefining how each frame of the video picture sequence will bemanipulated to represent the movement. Movements are usually required tobe smooth but not all addresses, either spatially or temporally, need tobe stored, because intermediate addresses may be calculated byextrapolation. Thus in defining a movement only certain addresses forso-called “key” frames, i.e. image frames having a position actuallydefined by the operator, need to be stored and intermediate frames canbe calculated by extrapolation between key frame addresses. Thus forexample, a pendulum movement of the picture may be defined by movementalong the X axis about a higher level reference point. The positions ofmaximum displacement in such a move may be defined as key frames andintermediate frames may be automatically calculated. The pendulum effectis then created by running the system and its speed is determined by thenumber of intermediate frames of the input picture sequence which aregenerated between key frames.

For a particular video production, and for future general reference, anoperator may store a library of effects on a disc memory device whichprovides fast and substantially random access loading of data to thesystem's transforming circuit 25. Effects are difficult to describe andclassify in a way which has any obvious meaning and therefore aparticular previously defined effect will usually be arranged to belocated by the user by previewing a number of effects from disc. Theprovision of the graphics store 27 also allows additional features to beprovided which are not present in hitherto known systems. In accordancewith another feature of this embodiment, the system may advantageouslybe arranged to display on the monitor address data in the form of alocus which shows the movement of a predetermined picture element overthe duration of the effect. The locus, or string, represents themovement over time of the effect and thus may be previewed by the userto assist in the identification of a previously defined effect.

FIG. 3 of the accompanying drawings is an exemplary showing of the locus40 of the centre point of the picture, i.e. the origin of axes 31, whichconstitutes in this example the abovementioned predetermined pictureelement. Locii be displayed representing movement of the origin of eachset of axes in the corresponding colour associated with that level. Thelocus 40 thus may be displayed as indicated schematically in FIG. 3 as aseries of segments 41 to 44 etcetera alternating in colour between therelevant level colour and another predetermined colour, say black. Thepoints 45 to 49 at which segments meet represent the positions of framesof the video image, and the number of segments along the locus 40represents the speed of the effect. A relatively large number of smallsegments will thus represent a slow effect, whereas a few large segmentswill represent a fast effect. The positions of key frames may beidentified by markers such as the small lines 50 that are shown in FIG.3 extending perpendicularly to the locus 40 at the relevant positions.

Locii are calculated using the same process that is used on each imagepicture point during the effect. As is known for example from commonlyassigned European Patent Application, Publication No. EP-A-0283159aforementioned three dimensional movement of a picture which gives riseto new co-ordinates (x′,y′,z′) in three dimensional space can be definedas a function of the original coordinate (x, y) in the two dimensionalspace of the monitor display. Once defined, the three dimensionalcoordinates are then projected onto the two dimensional plane of themonitor display screen and this gives new two dimensional co-ordinates(x′, y″) as functions of the three dimensional co-ordinates. Themovement of the picture may therefore be defined as two functionsdefining the positions of x″ and y″ with respect to the original x and ycoordinates. Thus x″, y″ coordinates are calculated for the centre ofthe image for each frame making up the effect.

Once a locus or string 40 has been calculated and displayed on themonitor 20, via graphics store 27, it can be put to other uses inaddition to assisting identification of the nature of the effect. Thesystem can be arranged so that the locus may be modified interactivelyby operation of the stylus 21 upon the touch tablet 22 with the modifiedcoordinates then being fed to the computer 24 to define the position ofnew key frames. Once a new key frame position has been set, a linecurving algorithm can be used to reposition other frames to maintain asmooth movement effect over time. As the cursor moves over a locus itjumps between the discrete frame positions 45 to 49 for example. A framerepresenting the shape of the picture at each frame position on thelocus can also be displayed. Thus the shape of the locus in 3D space canbe changed by moving the cursor to a point 45 to 49 and dragging thepoint to a new 3D position. A frame moved in this way need not be a keyframe, it can instead be an intermediate frame, but it will become a keyframe once it has been repositioned.

There has thus been described a video processing system for use increating three dimensional movement of a video image on a display screen20. At least one set of axes is displayed on the display screen and acomputer 24, in response to signals from a user operated stylus 21 andtouch tablet 22, controls the manipulation of image data in an imagestore 26 to control rotational or translational movement of the image,with respect to an axis selected by the user. In the describedembodiment several sets of linked axes may be defined. Rotational andtranslational movement with respect to an axis is controlledrespectively by selecting a marker identifying the axis or by selectinga line representing the axis. Selection is made by way of a cursor underthe control of the stylus and touch tablet. The system can also displaya locus representing the user defined movement of e.g. the centre of theimage.

Having thus described the present invention by reference to a preferredembodiment it is to be well understood that the embodiment in questionis exemplary only and that modifications and variations such as willoccur to those possessed of appropriate knowledge and skills may be madewithout departure from the spirit and scope of the invention as setforth in the appended claims and equivalents thereof.

What is claimed is:
 1. A video processing system for use in creatingthree dimensional movement of a video picture on a display screen, thesystem comprising: a source of video data representing a video picture;a user operable input device for generating control data in response touser manipulation thereof; a transforming circuit responsive to saidcontrol data from said user operable input device for effectingtransformations to the video data such that when the video picturerepresented by the video data is displayed on a display screen thepicture appears to move during a period of time in three dimensionalspace; a locus data generator responsive to said transforming circuitfor generating locus data representing a locus which depicts movement ofa predetermined element of said video picture during said threedimensional movement over time; and a monitor connected to receive saidlocus data for display of the locus thereon.
 2. A system as claimed inclaim 1, further comprising: a processor responsive to saidtransformation to the data for processing said video data to createprocessed video data representing the video picture as moved inthree-dimensional space; and a combining circuit for combining thetransformed video data processed by the processor and the locus data toproduce combined data representing a picture, transformed in accordancewith said transformations to the data, in combination with said locusand wherein said monitor is connected to receive said combined data fordisplaying the transformed picture in combination with said locus.
 3. Asystem as claimed in claim 2, wherein said user operable input devicecomprises a pressure sensitive stylus and a touch tablet, the systemfurther comprising: a cursor generator for generating cursor datarepresenting a cursor for display by the display screen, the cursor datarepresenting the cursor at a position determined by user manipulation ofsaid user operable input device; and a generator for generating axesdata representing a set of axes having a predetermined positionalrelationship to the picture for display with the picture, the combiningcircuit being arranged to combine the axes data with said video datasuch that the combined signal represents the set of axes positioned atthe center of the picture, thereby enabling manipulation of the pictureto be effected by display of the set of axes on said display screen andby rotation and/or translation of said picture by selection of said setof axes by positioning of the displayed cursor under the control of saiduser operable input device.
 4. A system as claimed in claim 2, furthercomprising a key position defining circuit responsive to usermanipulation of said user operable input device for defining thepositions in three-dimensional space of at least some manipulated framesof the video picture selected as key frames by said user manipulation ofsaid user operable input device; and wherein said locus data generatoris responsive to said key position defining circuit to generate a locusincluding an indication of the positions of said key frames, and saidprocessor includes circuitry for calculating automatically the positionsof frames between the selected key frames.
 5. A system as claimed inclaim 4, further comprising an interpolating circuit for calculating byinterpolation between user defined key frames the positions of otherframes in the sequence not having a user defined position.
 6. A systemas claimed in claim 1, in which the locus data generator is arranged togenerate locus data in which the location of key frames in the movementare represented by first markers in the locus and the locations of otherframes are represented by second markers in the locus.
 7. A system asclaimed in claim 1, wherein the locus data generator is arranged togenerate data representing a locus having markings depicting the speedof movement of the video picture three-dimensional space.
 8. A videoprocessing method for use in creating apparent three dimensionalmovement of a video picture on a display screen, the method comprising:providing a source of video data representing a video picture;generating control data in response to a user operable input; atransformation step, in response to the control data from said useroperable input step, for performing transformations to the video datasuch that when the video picture represented by the video data isdisplayed on a display screen the picture appears to move during aperiod of time in three dimensional space; a locus generating step, inresponse to said transformation step, for generating locus datarepresenting a locus which depicts movement of a predetermined elementof said video picture during said three dimensional movement over time;and a display step for displaying the locus thereon.
 9. A method asclaimed in claim 8, further comprising: a processing step, in responseto said transformation step, for processing said video data to createprocessed video data representing the video picture as moved inthree-dimensional space; and a combining step for combining thetransformed video data processed by the processing step and the locusdata to produce combined data representing a picture, transformed inaccordance with said transformations to the data, in combination withsaid locus and wherein said display step receives said combined data fordisplaying the transformed picture in combination with said locus.
 10. Amethod as claimed in claim 9, wherein said user operable input comprisesinputting data via a pressure sensitive stylus and a touch tablet, themethod further comprising: a cursor generating step for generatingcursor data representing a cursor for display by the display screen, thecursor data representing the cursor at a position determined by saiduser operable input; and a generating step for generating axes datarepresenting a set of axes having a predetermined positionalrelationship to the picture for display with the picture, the combiningstep combining the axes data with said video data such that the combineddata represents the set of axes positioned at the center of the picture,thereby enabling manipulation of the picture to be effected by displayof the set of axes and by rotation and/or translation of said picture byselection of said set of axes by positioning of the displayed cursorunder the control of said user operable input step.
 11. A method asclaimed in claim 9, further comprising a key position defining stepresponsive to said user operable input for defining the positions inthree-dimensional space of at least some manipulated frames of the videopicture selected as key frames by said user operable input; and whereinsaid locus data generating step is responsive to said key positiondefining step to generate a locus including an indication of thepositions of said key frames, and said processing step calculatesautomatically the positions of frames between the selected key frames.12. A method as claimed in claim 11, further comprising an interpolatingstep for calculating by interpolation between user defined key framesthe positions of other frames in the sequence not having a user definedposition.
 13. A method as claimed in claim 8, in which the locus datagenerator step generates locus data in which the locations of key framesin the movement are represented by first markers in the locus and thelocations of other frames are represented by second markers in thelocus.
 14. A system as claimed in claim 8, wherein the locus datagenerating step generates data representing a locus having markingsdepicting the speed of movement of the video picture inthree-dimensional space.